resourcebundleelresolver.java

梅花雪树的经典制作

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package javax.el;

import java.beans.FeatureDescriptor;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

public class ResourceBundleELResolver extends ELResolver {

	public ResourceBundleELResolver() {
		super();
	}

	public Object getValue(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}
		
		if (base instanceof ResourceBundle) {
			context.setPropertyResolved(true);

			if (property != null) {
				try {
					return ((ResourceBundle) base).getObject(property
							.toString());
				} catch (MissingResourceException mre) {
					return "???" + property.toString() + "???";
				}
			}
		}

		return null;
	}

	public Class<?> getType(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}
		
		if (base instanceof ResourceBundle) {
			context.setPropertyResolved(true);
		}
		
		return null;
	}

	public void setValue(ELContext context, Object base, Object property,
			Object value) throws NullPointerException,
			PropertyNotFoundException, PropertyNotWritableException,
			ELException {
		if (context == null) {
			throw new NullPointerException();
		}
		
		if (base instanceof ResourceBundle) {
			context.setPropertyResolved(true);
			throw new PropertyNotWritableException(message(context,
					"resolverNotWriteable", new Object[] { base.getClass()
							.getName() }));
		}
	}

	public boolean isReadOnly(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}
		
		if (base instanceof ResourceBundle) {
			context.setPropertyResolved(true);
		}
		
		return true;
	}

	public Iterator getFeatureDescriptors(ELContext context, Object base) {
		if (base instanceof ResourceBundle) {
			List<FeatureDescriptor> feats = new ArrayList<FeatureDescriptor>();
			Enumeration e = ((ResourceBundle) base).getKeys();
			FeatureDescriptor feat;
			String key;
			while (e.hasMoreElements()) {
				key = (String) e.nextElement();
				feat = new FeatureDescriptor();
				feat.setDisplayName(key);
				feat.setExpert(false);
				feat.setHidden(false);
				feat.setName(key);
				feat.setPreferred(true);
				feat.setValue(RESOLVABLE_AT_DESIGN_TIME, Boolean.TRUE);
				feat.setValue(TYPE, String.class);
				feats.add(feat);
			}
			return feats.iterator();
		}
		return null;
	}

	public Class<?> getCommonPropertyType(ELContext context, Object base) {
		if (base instanceof ResourceBundle) {
			return String.class;
		}
		return null;
	}

}